Help on the apparent heat source Q1

[Wesley Ebisuzaki]

Dear Louis,

   It should be possible to do the calculation with GrADS but you would
get better results
if you were to reprocess the pressure-level grib data from the sigma
analyses.  By modifying
the "pgb" program, you can get

   (1) more precision (grib has a  creation-time specified precision)
   (2) more and evenly spaced vertical levels
   (3) finer horizontal resolution (I not sure how hard this is)

The calculated values in the stratosphere have problems but the
troposphere looks good.
BTW the R2 (NCEP/DOE Reanalysis) has has a complete set of sigma files
on-line
on http://nomad3.ncep.noaa.gov, so you may have to use R2.

 Wesley Ebisuzaki

pgb:  ftp://ftp.cpc.ncep.noaa.gov/wd51we/reanl_software


louis Vonder wrote:
> Dear Grads users,
>
> I am trying to compute the apparent heat source Q1 using NCEP/NCAR
> with grads.
>
> Q1 = ds/dt + V.grad(s) + omega*ds/dp
>
> Where
> s = cpT + gZ,
> V = horizontal wind
> grad = gradient
> d/dt = time partial derivative
> d/dp = pressure partial derivative
> T =temperature
> Z=geopotential
> omega = vertical velocity
>
> There is a way  to do it in grads?
>
> Thanks
>
>
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